The present disclosure is directed to high pressure fluid rotary nozzle systems. In particular, embodiments of the present disclosure are directed to an apparatus for retarding the rotational speed of such rotary nozzles.
A high pressure rotary nozzle and tractor device is disclosed in US Patent Application Publications 2012/0204368 and 2012/0205405. Such nozzles and tractor devices are particularly well suited to industrial uses where the operating parameters can be in the range of 1,000 to 40,000 psi, rotating speeds of up to 1000 rpm or more and flow rates of 2 to 50 gpm may be needed.
In order to control the rotational speed of the rotary nozzle and tractor devices, there is a need for a speed control to retard the speed of the tool to keep the rpm's in a desired range for specific cleaning applications. There are several different speed control mechanisms, one of which, described in U.S. Pat. No. 5,964,414 utilizes viscous fluid within stacked radial ball bearings within a sealed bearing chamber in the body rotatably supporting the shaft. Another mechanism includes a viscous fluid confined within a thin gap that separates two components where one component is rotated and the other is stationary. This speed control style can handle a limited input torque range based on the set distance of the gap. This limit in torque range requires that other components on the rotary nozzle be changed to accommodate major variations in flow and pressure. What is still needed is an apparatus that can be utilized over a wide torque range to reliably control rotational speed.